Effective Isolation of structures from external vibrations by means of discrete media Hasson Tavossi, Department of Engineering Technology, Savannah State University, 3219 College St. Savannah, GA 31404.

Wave properties of the particulate media are explored to determine their vibration attenuation, by absorption and scattering of mechanical waves, as a function of material parameters, with the goal to effectively reduce vibration transmission into structures. Pressure wave, shear wave, and surface waves are considered. Wave speeds and attenuation in the discrete media depend on mechanical parameters of the media. Among these are; particulate size distribution, confining pressure, contact areas, and the compactness. Experimental results presented show that; for a fixed value of parameter; discrete media strongly attenuate vibrations in a frequency-band, and transmit vibrations outside that band. Different samples of particulates are subjected to mechanical vibrations, within a range of frequency and amplitude in direct contact with samples. Measurement of attenuation, transmitted intensity, and wave speed are presented with different media parameter. Experimental findings on attenuation as a function of frequency and intensity, and dispersion curve can provide discrete media properties for more effective means to attenuate of external vibrations transmitted into a structure.